A brake system for rail cars comprising an intensifier, a spool valve, a pump, and at least two hydraulic or air cylinders.
The rail network in North America is the largest in the world, operating with the high axle loads customarily used with heavy freight hauling railways. For many years there has been a trend in North America to use heavier and heavier freight cars. This trend has required designers of brake systems to attempt to pack more and more brake performance into a smaller and smaller space.
In a paper presented at the September, 1971 Annual Meeting of the Air Brake Association (1971). Thomas H. Engle, Senior Project Engineer of the New York Air Brake Company (of Starbuck Avenue, Watertown, N.Y.) disclosed that xe2x80x9cAbout four years ago, our Company decided that in the long run the best solution for this squeeze would be a hydro-pneumatic braking system which included both hand and power braking, and which would use a mechanical lock on the handbrake so as to hold a car, on which handbrakes had been applied, even in the absence of hydraulic pressure.xe2x80x9d
In 1972, U.S. Pat. No. 3,707,309 was issued to Mr. Engle. This patent claimed a fluid operated brake system for a railway car which comprised a hydraulic hand brake control unit which had to be manually activated and deactivated. Failure to deactivate the control unit at the appropriate time causes the brakes to maintain contact with the wheels, thus increasing wear and tear upon the system and leading to premature failure.
By no later Mar. 16, 1976, when U.S. Pat. No. 3,944,286 issued to Thomas H. Engle, there existed, according to such patent, xe2x80x9c . . . railway regulations which require a crewman to move or confirm all parking brakes to an xe2x80x98OFFxe2x80x99 position . . .  xe2x80x9d The patent disclosed that xe2x80x9cThe prior art systems . . . may create problems in use since it is frequently the case that the parking brake has not been fully unlocked and released by a crewman before an attempt is made to move the car. Obviously, this can cause numerous delays to locate the stuck brakes, undue brake wear if some movement does occur and similar deleterious effects.xe2x80x9d The solution to this problem presented in this patent was to provide a brake system which first required a crewman to release the parking brake of a particular car. The patentees disclosed that xe2x80x9cIf, however, the crewman has failed to even partially release the parking brake of a particular car, the booster 70 will be ineffective to release either the brake or the brake locking mechanism.xe2x80x9d
Some twenty-three years later, when Thomas H. Engles""s U.S. Pat. No. 5,746,293 issued in May of 1998, the problems discussed in his earlier patent had not been solved. Thus, as is disclosed at lines 50-55 of column 1 of this 1998 Engle patent, xe2x80x9c . . . these hand brakes have been a source of problems. This is particularly the case when such hand brakes are not released when a train consist is ready to move over the tracks . . .  xe2x80x9d
About the same time that U.S. Pat. No. 5,746,293 issued to Mr. Engle, U.S. Pat. No. 5,767,973 issued to Hans J. Naumann. This latter patent disclosed that xe2x80x9c . . . the rail network in the North America is . . . characterized by an inordinately high number of railroad accidents and derailments; these incidents occur at a substantially higher rate in North America than anywhere else in the world.xe2x80x9d
Applicant believes that one of the causes of this problem is a failure to properly operate and maintain the braking systems on rail cars. Such lack of proper operation and maintenance is often due to the complexity of such systems, difficulty of access to the components in such systems, and the lack of readily apparent visual indicators warning of system status.
It is an object of this invention to provide a brake system which is more reliable than prior art brake systems.
It is another object of this invention to provide a brake system which allows ready visual access to determine whether the brakes are disengaged.
It is yet another object of this invention to provide a brake system which can readily be attached to conventional railway trucks.
It is yet another object of this invention to provide a brake system which can readily be removed from conventional railway trucks for service.
It is yet another object of this invention to provide a brake system which automatically disengages a hand brake upon application of a train""s service brake.
It is yet another object of this invention to provide a brake system which is relatively lightweight, small, and inexpensive.
It is yet another object of this invention to provide a brake system which can be used with a railway truck and a railway car.
It is yet another object of this invention to provide a brake system which will require substantially less maintenance than prior art braking systems, less time to do such maintenance, and less expense to do such maintenance.
In accordance this invention, there is provided a brake system for rail cars comprised of an intensifier, a spool valve connected to said intensifier, a pump connected to said spool valve, a first cylinder connected to said spool valve, and a second cylinder connected to said spool valve.